CLOTH FEED DEVICE FOR LOOMS

Abstract: A cloth feed device for looms, including a cloth drawing roller (11) on to which the cloth (S) produced on the loom immediately upstream from the feed device is wound over a given angle; at least one pressure roller (12) for pressing the cloth (S) on to the drawing roller (11); a supporting frame (13) integral with the loom; and drive means for rotating the drawing roller in a given direction in time with the loom, and collecting the cloth (S) on a winding roller (15); the drawing roller (11) being mounted for rotation on a pair of opposite supports (16, 18) in turn fitted in rocking manner to the frame by means of respective pivots (19, 20) coaxial with each other, eccentric in relation to the rotation axis of the drawing roller (11), and so arranged that the pull (TF) exerted by the cloth (S) presses the drawing roller (11) on to the pressure roller (12) which is supported idly in a fixed position on the frame.

Description: CLOTH FEED DEVICE FOR LOOMS TECHNICAL FIELD The present invention relates to a cloth feed device for looms, particularly continuous weft feed looms. BACKGROUND ART With reference to Figure 1, the cloth feed device on a loom provides for collecting the cloth S downstream from the weaving line where the warp yarns O are woven with the weft yarns by means of the heddles L and reed Y and then fed, in the form of cloth S, to a clot drawing roller T. On known feed devices, the cloth drawing roller is secured to the loom structure by means of lateral rotary connections which permit it to rotate but should prevent it from effecting any other movement. The cloth drawing roller is so covered as to draw forward cloth S which, downstream from the weaving line, moves in a more or less straight line for about 200-300 mm, and is then fed downwards and wound on to roller T about an angle A extending between the point at which the cloth engages roller T, and the point at which roller T is engaged by a pressure roller P also connected in rotary manner at the ends to the loom structure. The function of pressure roller P is to ensure a given tension Tf of the cloth, which depends on winding angle A and friction coefficient F according to the equation Tf = te FA , and which is achieved by pressing roller P on to roller T with the aid of lateral springs and the weight of the pressure roller itself, which is therefore of considerable size, roughly half that of roller T. The diameter of the rollers normally varies between 140-200 mm for T, and 50-100 mm for P, depending on the working width of the loom and the consistency of the cloth. In view of recent market demand for looms for producing increasingly heavy, napped fabrics, the above solution presents several drawbacks, mainly due to deformation of the two rollers - as a result of weight, in-service oscillation produced by the loom, and poor efficiency of the lateral connections - resulting in nonuniform pressure distribution, and in actual slippage of the cloth where insufficient pressure is exerted. Moreover, the size of the rollers occupies considerable space at the front of the loom, encumbers the work of the operator, and does not allow of large winding angles. DISCLOSURE OF INVENTION It is an object of the present invention to provide a cloth feed device for looms substantially of the aforementioned type but designed to overcome the aforementioned drawbacks, and which in particular is cheap to produce, compact and lightweight in design, and provides for a high degree of reliability. According to the present invention, there is provided a cloth feed device for looms, comprising a cloth drawing roller on to which the cloth produced on the loom immediately upstream from the feed device is wound over a given angle; at least one pressure roller for pressing the cloth on to the drawing roller; a supporting frame for said rollers, integral with the loom; and drive means for rotating the cloth drawing roller in a predetermined direction in time with the loom, and collecting the cloth on a cloth winding roller; characterized by the fact that it also comprises a pair of opposite lateral supports to which the cloth drawing roller is mounted for rotation; and connecting means for connecting said supports to the frame so that the supports are movable in relation to the pressure roller; said connecting means, as a consequence of the pull exerted by the cloth on the drawing roller, being designed to so move the lateral supports as to push the drawing roller into contact with the pressure roller. As such, the cloth drawing roller is greatly improved in terms of both operation and the working conditions of the operator, and may be reduced in size by as much as 60% as compared with known systems, thus greatly reducing the weight, size, and consequently also the cost of the device as a whole, due to the smaller size of the component parts. In addition to being more compact, the device also provides for greater efficiency by enabling larger winding angles of the cloth on the drawing roller; and, being less sensitive to vibration, provides for uniform distribution of the contact pressure between the drawing and pressure rollers. The traditional single pressure roller is preferably replaced by a pair consisting of straightforward idle rollers much smaller in diameter than the drawing roller, and fitted side by side, on the opposite side to that at which the cloth engages the drawing roller, to a longitudinal gantry type element perpendicular to the cloth feed direction and locked in a fixed position to the frame so that the cloth leaving the pressure roller/s and directed towards the winding roller runs outside the gantry element. As such, the supporting element of the pressure roller/s may be anchored to the main structural members of the loom not only at the ends but also along the longitudinal axis by means of a number of intermediate supports, thus providing for greater rigidity and, hence, optimum engagement of the drawing and pressure rollers, and a drastic reduction in flexural strain. Moreover, the device as a whole vibrates differently as compared with known devices, being characterized by higher-frequency but lower-amplitude vibration. This is extremely important when weaving delicate fabrics, such as veiling, which, by introducing a limited amount of damping, may undergo nonuniform weaving, due to excessively high-amplitude oscillation of the drawing roller which, reflected in the position of the weaving line in relation to travel of the reed, results in an appreciable variation in the density of the fabric. Finally, the pressure rollers are preferably mounted idly inside respective side by side seats formed symmetrically on a rocker arm element fitted to the gantry element and free to rock about an axis parallel to the rotation axis and between the seats of the rollers, thus providing for self-centering the assembly consisting of the drawing roller and the two pressure rollers. According to a preferred embodiment, the gantry element supporting the pressure rollers comprises rotation means for rotating at least one portion of the gantry element, with a rotation seat for the pressure roller/s, about an axis parallel to and eccentric in relation to those of the rollers and beneath the center line of the drawing roller; and means for locking said rotation means, for selectively supporting the pressure roller/s in a fixed position on the frame, and tilting at least said portion of the supporting element away from the drawing roller, thus enabling fast, easy access to at least the front part of the drawing roller when inserting the cloth at each changeover. BRIEF DESCRIPTION OF DRAWINGS A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a schematic longitudinal view of a loom featuring a known cloth feed device; Figure 2 shows a larger-scale, schematic detail of the Figure 1 loom on which the known feed device is replaced by a cloth feed device in accordance with the present invention; Figures 3 and 4 show top plan views of two variations of a detail on the Figure 2 device; Figures 5, 6 and 7 show, schematically, different means for driving the device according to the present invention; Figure 8 shows a schematic view of a preferred embodiment of the cloth feed device according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Number 1 in Figures 1 and 2 indicates a loom, in the example shown a continuous weft feed loom, having a fixed load-bearing structure or frame 2 to which are fitted the functional parts substantially comprising a known warp yarn feed device 3, and a known cloth forming line 4 defined between heddles L and a reed Y (Figure l) . The warp yarns are woven in known manner with the weft yarns (not shown) and form cloth S downstream from reed Y which is shown in its two limit operating positions (by the dotted and continuous line respectively) . With reference to Figures 2 to 5, number 10 indicates a cloth feed device in accordance with the present invention and advantageously fittable to loom 1 in place of the known device shown by way of comparison in Figure 1. Device 10 comprises a cloth drawing roller 11 (replacing roller T) on to which the cloth S produced on loom 1 immediately upstream from feed device 10 is wound over a given angle A; and at least one pressure roller 12 (in the non-limiting example shown, two side by side rollers 12) for pressing cloth S on to drawing roller 11, and replacing the traditional roller P in Figure 1. Rollers 11, 12 are supported, as will be seen, on a frame 13 integral, in use, with loom 1 by being formed in one piece with or fittable in known manner (not shown) to the load-bearing structure or frame 2 of loom 1. Feed device 10 also comprises drive means (Figures 5 to 7) for rotating drawing roller 11 in a given direction (arrow 14 in Figure 2) in time with loom 1, and collecting cloth S downstream from forming line 4 - in the example shown, on a cloth winding roller 15 identical to that of the known feed device in Figure 1. As shown in Figures 2, 3 and 4, the main characteristic of device 10 is that of comprising, in combination, a pair of opposite lateral supports 16 and 18 to which drawing roller 11 is fitted for rotation in any known manner; and special connecting means 19, 20 for so connecting supports 16, 18 to frame 13 that the supports are both secured stably to frame 13 and movable relative to the same in relation to the two pressure rollers 12. Rollers 12 consist of straightforward idle rollers much smaller in diameter than drawing roller 11, and fitted side by side to a longitudinal gantry type element 21 (Figures 2 and 4) . Element 21 supports rollers 12 idly and parallel to roller 11, on the opposite side of roller 11 to that engaged by cloth S and located immediately downstream (in the rotation direction indicated by arrow 14) from the substantially straight portion u-v of tensioned cloth S from forming line 4. Element 21 is located perpendicular to the feed direction of cloth S (indicated by arrow 22 in Figure 2) , and is locked, in use, in a fixed position on frame 13; which position and the contour of element 21 are so selected that cloth S leaving the last pressure roller 12 and directed towards winding roller 15 is forced to travel outside element 21 as shown clearly in Figure 2. As such, the rigidity of longitudinal gantry element 21 may be enhanced as compared with that of drawing roller 11, by securing it to frame 13 (Figure 4) not only at the opposite ends 23 (only one shown in Figure 4) but also at one or more intermediate points by means of respective end and intermediate supporting arms 24 and 25 projecting from frame 13 (in the example shown, directly from frame 2 of loom 1) immediately upstream from drawing roller 11 (substantially at portion u-v) and lower down than roller 11. The greater rigidity of element 21 as compared with roller 11 provides for reducing the overall flexural strain of the components of device 10 as a whole. According to the present invention, connecting means 19, 20 are so designed as to move lateral supports 16, 18, as a consequence of the pull exerted by the cloth on drawing roller 11, and so push roller 11 stably and in balanced manner on to pressure roller/s 12. In the example shown, connecting means 19, 20 consist of a pair of respective opposite coaxial pivots fixed to frame 13 and eccentric in relation to the rotation axis of both drawing roller 11 and pressure roller/s 12, so that lateral supports 16, 18, to which roller 11 is fitted for rotation, are in turn fitted to frame 13 so as to rock about pivots 19, 20 and about an axis parallel to roller 11. According to a variation not shown, straightforward pivots 19, 20 may be replaced by other connecting elements, e.g. pads sliding inside appropriately shaped guides. According to the preferred embodiment shown, the two pressure rollers 12 are fitted to supporting element 21 so that the resultant (Tf in Figure 2) of the forces exerted by rollers 12 on roller 11 as a consequence of the pull exerted by cloth S is directed parallel to tensioned cloth portion u-v preceding engagement of drawing roller 11, and passes inside the gap between rollers 12 and through the rotation axis of drawing roller 11. In particular, and as shown in the preferred variation in Figure 8, pressure rollers 12 are mounted idly inside respective side by side seats 30 formed symmetrically on a rocker arm element 31 hinged at 3la to gantry element 21 so as to rock about an axis parallel to the rotation axis and between seats 30 of rollers 12. For improving access to roller 11 by the operators, element 21 may be formed in two parts hinged to each other. As shown in Figure 8, gantry element 21 supports the two pressure rollers 12 immediately downstream from and above the center line of drawing roller 11, and is divided into a portion 33 integral with end supporting arms 24 (and intermediate supporting arms 25, if any) ; and a portion 32 to which rocker arm 31 supporting rollers 12 inside seats 30 is hinged, and which is in turn hinged at 35 to portion 33 so as to rock selectively, about an axis parallel to and eccentric in relation to the axes of rollers 11, 12 and below the center line of drawing roller 11, between two limit positions shown respectively by the dotted and continuous lines in Figure 8. In the position shown by the continuous line, portion 32 rests on portion 33 so that rollers 12 are set to the operating position facing roller 11; and movable portion 32 may be locked mechanically on to fixed portion 33 using any known rotation lock means, e.g. bolts 36, so as to support pressure rollers 12 in a fixed position on frame 13. In the position shown by the dotted line, on the other hand, portion 32 is tilted laterally away from drawing roller 11, so as to detach rollers 12 from roller 11 and enable troublefree access from outside loom 1 to at least the front part of roller 11. Again with reference to the preferred variation in Figure 8, between frame 13 (or frame 2 directly) and the rocking lateral supports 16, 18 of drawing roller 11, provision may be made for elastic reaction elements 40 for maintaining contact between drawing roller 11 and rollers 12 (in the work position) even in the event of no pull being exerted by cloth S. In the example shown, supports 16, 18 present opposite ends fitted respectively with roller 11 and springs 40, and along the center line engage pivots 19, 20, so that appropriate pretensioning of springs 40 provides for maintaining a given contact pressure between roller 11 and rollers 12. With reference to Figure 5, said drive means for rotating drawing roller 11 on supports 16, 18 and in time with loom 1 comprise a geared motor 50 fitted directly to one of supports 16, 18 - in the example shown, support 16 - and acting directly on drawing roller 11 via a gear drive 51. In this case, timing is achieved by means of appropriate electronic control of motor 50. According to the variation shown in Figure 6, roller 11 of device 10 is driven directly by a motor 52 fitted to frame 2 of loom 1, and which, by means of a known mechanical drive 53, provides for driving all the devices on loom 1, so that timing is assured mechanically. In this case, the drive means comprise wheel drive means 56, 57 (gears or pulleys) ; and flexible endless elements 58 (chains or belts, smooth or toothed) ; and, for enabling simultaneous drive and rocking of roller 11, the rotation axis of driven wheel 57 coincides with that of pivots 19, 20, so that the wheel may be mounted on one of the pivots together with the corresponding support 16 or 18, for transmitting motion, for example, by means of a gear train 59. Finally, the Figure 7 variation provides for mechanical timing, as in Figure 6, but is particularly useful in the case of a motor 52 (not shown) mounted at the rear of loom 1 with a propeller shaft 60 substantially perpendicular to the axis of roller 11. In this case, an articulated joint 61, e.g. a universal joint, is provided on shaft 60 at the axis of pivots 19, 20, which provision is more than sufficient for drive purposes in view of the limited travel (about 10 mm) of roller 11.

Claims: CLAIMS 1) A cloth feed device for looms, comprising a cloth drawing roller on to which the cloth produced on the loom immediately upstream from the feed device is wound over a given angle; at least one pressure roller for pressing the cloth on to the drawing roller; a supporting frame for said rollers, integral with the loom; and drive means for rotating the cloth drawing roller in a predetermined direction in time with the loom, and collecting the cloth on a cloth winding roller; characterized by the fact that it also comprises a pair of opposite lateral supports to which the cloth drawing roller is mounted for rotation; and connecting means for connecting said supports to the frame so that the supports are movable in relation to the pressure roller; said connecting means, as a consequence of the pull exerted by the cloth on the drawing roller, being designed to so move the lateral supports as to push the drawing roller into contact with the pressure roller. 2) A cloth feed device as claimed in Claim 1, characterized by the fact that, between the frame and said movable lateral supports of the drawing roller, elastic reaction elements are provided for maintaining the drawing roller in contact with the pressure roller, even in the event of no pull being exerted by the cloth. 3) A cloth feed device as claimed in Claim 1 or 2, characterized by the fact that said connecting means comprise a pair of respective opposite coaxial pivots fixed to the frame and eccentric in relation to the rotation axis of both the drawing roller and the pressure roller; said lateral supports being fitted to the frame so as to rock about said pivots. 4) A cloth feed device as claimed in one of the foregoing Claims, characterized by the fact that the pressure roller is fitted idly, on the opposite side to that on which the cloth engages the drawing roller, to a longitudinal gantry type element perpendicular to the cloth feed direction and locked, in use, in a fixed position on the frame, so that the cloth leaving the pressure roller and directed towards the cloth winding roller travels outside said gantry element. 5) A cloth feed device as claimed in Claim 4, characterized by the fact that said longitudinal gantry element supporting the pressure roller presents a greater rigidity than the drawing roller. 6) A cloth feed device as claimed in Claim 4, characterized by the fact that said longitudinal gantry element supporting the pressure roller is connected to the frame both at its opposite ends and at least one intermediate point by means of respective supporting arms projecting from the frame immediately upstream from and below the drawing roller. 7) A cloth feed device as claimed in one of the foregoing Claims from 4 to 6, characterized by the fact that said longitudinal gantry element supports the pressure roller immediately downstream from, above the center line of, and parallel to the drawing roller; and comprises rotation means for rocking at least one portion of said gantry element, having a rotation seat for said pressure roller, about an axis parallel to and eccentric in relation to the axes of said rollers and below the center line of the drawing roller; and means for locking said rotation means, for selectively supporting the pressure roller in a fixed position on the frame, and enabling at least said portion of the supporting element to be tilted away from the drawing roller for enabling access to at least the front part of the drawing roller. 8) A cloth feed device as claimed in one of the foregoing Claims from 4 to 7, characterized by the fact that it comprises a pair of pressure rollers consisting of straightforward idle rollers much smaller in diameter than the drawing roller and fitted side by side to said longitudinal gantry element, so that the resultant of the forces exerted by said rollers on the drawing roller, as a consequence of the pull exerted by the cloth, is directed parallel to the tensioned cloth portion preceding engagement of the drawing roller, and passes inside the gap between the two pressure rollers and through the rotation axis of the drawing roller. 9) A cloth feed device as claimed in Claim 8, characterized by the fact that said pressure rollers are mounted idly inside respective side by side seats formed symmetrically on a rocker arm element fitted to said gantry element so as to rock about an axis parallel to the rotation axis and between the seats of the rollers. 10) A cloth feed device as claimed in any one of the foregoing Claims, characterized by the fact that said drive means for rotating the drawing roller comprise a geared motor fitted to one of said lateral supports and acting directly on the drawing roller. 11) A cloth feed device as claimed in any one of the foregoing Claims from 3 to 9, characterized by the fact that said drive means for rotating the drawing roller comprise wheel drive means, flexible endless elements, and a motor integral with the frame; the rotation axis of one of said wheels coinciding with that of one of said pivots. 12) A cloth feed device as claimed in any one of the foregoing Claims from 3 to 9, characterized by the fact that said drive means for rotating the drawing roller comprise shaft and gear drive means including at least one shaft perpendicular to the rotation axis of the drawing roller, a motor integral with the frame, and an articulated joint on said shaft at the axis of said pivots. 13) A cloth feed device for looms, substantially as described and illustrated herein with reference to the accompanying drawings.

Inventors: BONACINA CARLO, BONACINA, CARLO
Applicants: BONACINA CARLO, INTERPATENTS LTD, BONACINA, CARLO, INTERPATENT LIMITED
Application year: 1994
Main classification: D03D49
IPC codes: D03D49